You have the following number:
1.75
This number can be considered as a RATIONAL number and REAL number.
It's rational because is a simple decimal that can be written as a fraction. In this case there are no infinite digits that are not periodic. It's real because all rational numbers are real numbers.
An integer number is a number that can be writen without decimals digits. So, 1.75 is not an integer.
An irrational number is a number with many decimal digits without periodicity. For example:
2.3434343434 This is a periodic number (it's not irrational)
2.3486720036 Here you can not identiy a periodicity (it`s rational)
Real numbers are all numbers, integers, rational, irrational, etc